Clip-on adapter for simultaneous inline Raman and fluorescence spectroscopy inside semitransparent plastic pipes

Area of Science:

• Analytical Chemistry
• Chemical Engineering
• Spectroscopy

Background:

• Continuous microflow reactors offer precise control over chemical processes.
• Inline monitoring is crucial for real-time reaction analysis and optimization.
• Standard Raman probes require specialized integration for microflow systems.

Purpose of the Study:

• To develop and present a versatile clip-on adapter for integrating standard Raman probes into microflow reactor systems.
• To enable simultaneous Raman and fluorescence spectroscopy for comprehensive inline chemical analysis.
• To demonstrate the adapter's utility in real-time reaction monitoring and control.

Main Methods:

• A clip-on adapter was designed to fit standard Raman probes (9.5 mm diameter) onto semitransparent tubes (6.35 mm OD).
• The adapter facilitates inline spectroscopic measurements in reflection (Raman) and 90° (fluorescence) modes.
• Simultaneous Raman and fluorescence spectroscopy were applied to analyze vegetable oil mixtures and monitor esterification reactions.

Main Results:

• The adapter allows flexible positioning on fixed or flexible tubing for adaptable inline measurements.
• Demonstrated simultaneous Raman and fluorescence detection for analyzing complex mixtures like vegetable oils.
• Investigated the impact of integration time and flow rate on signal intensity for olive oil analysis.
• Successfully applied non-contact inline Raman monitoring for acid-catalytic esterification of ethyl acetate.

Conclusions:

• The developed clip-on adapter provides a simple and effective solution for inline spectroscopic analysis in microflow reactors.
• Simultaneous Raman and fluorescence spectroscopy offer enhanced capabilities for real-time process monitoring and control.
• This technology facilitates improved understanding and optimization of chemical reactions in continuous flow systems.